Galatians 2:11-13

11Now when Cephas (Peter) came to Antioch, I opposed him face to face [about his conduct there], because he stood condemned [by his own actions].

12Before certain men came from James, he used to eat [his meals] with the Gentiles; but when the men [from Jerusalem] arrived, he began to withdraw and separate himself [from the Gentile believers], because he was afraid of those from the circumcision.

13The rest of the Jews joined him in this hypocrisy [ignoring their knowledge that Jewish and Gentile Christians were united, under the new covenant, into one faith], with the result that even Barnabas was carried away by their hypocrisy.